Re: [PATCH 4/5] usb: dwc3: qcom: Clear pending interrupt before enabling wake interrupt

[Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>]

On Tue, Mar 28, 2023 at 11:28:32AM +0200, Johan Hovold wrote:
> On Sat, Mar 25, 2023 at 10:22:16PM +0530, Manivannan Sadhasivam wrote:
> > It is possible that there may be a pending interrupt logged into the dwc IP
> > while the interrupts were disabled in the driver. And when the wakeup
> > interrupt is enabled, the pending interrupt might fire which is not
> > required to be serviced by the driver.
> > 
> > So always clear the pending interrupt before enabling wake interrupt.
> > 
> > Cc: stable@vger.kernel.org # 5.20
> > Fixes: 360e8230516d ("usb: dwc3: qcom: Add helper functions to enable,disable wake irqs")
> > Signed-off-by: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
> > ---
> >  drivers/usb/dwc3/dwc3-qcom.c | 2 ++
> >  1 file changed, 2 insertions(+)
> > 
> > diff --git a/drivers/usb/dwc3/dwc3-qcom.c b/drivers/usb/dwc3/dwc3-qcom.c
> > index bbf67f705d0d..f1059dfcb0e8 100644
> > --- a/drivers/usb/dwc3/dwc3-qcom.c
> > +++ b/drivers/usb/dwc3/dwc3-qcom.c
> > @@ -346,6 +346,8 @@ static void dwc3_qcom_enable_wakeup_irq(int irq, unsigned int polarity)
> >  	if (!irq)
> >  		return;
> >  
> > +	irq_set_irqchip_state(irq, IRQCHIP_STATE_PENDING, 0);
> > +
> 
> This looks like a hack (and a layering violation). Note that there are
> no other non-irqchip drivers calling this function.
> 

I can check if this can be achieved by clearing some dwc specific registers.

- Mani

> >  	if (polarity)
> >  		irq_set_irq_type(irq, polarity);
> 
> Johan

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